The After-School Corporation (TASC) has completed its sixth year of operations, working with public and private partners across New York City and the state to develop and operate school-based after-school services for public school students in the elementary and secondary grades. Since its founding in 1998, TASC has emphasized twin goals of increasing the availability of after school opportunities and enhancing the quality of after-school services. To assess TASC's effectiveness, four foundations including the Charles Stewart Mott Foundation, the Carnegie Corporation of New York, the William T. Grant Foundation, and the Atlantic Philanthropies supported an external evaluation that answered questions about: quality and scale in program implementation, program effects on participating students, and program practices linked to student success. The evaluation collected data over four school years from 96 TASC after-school projects and their host schools in New York City. Its student sample numbered 52,000 after-school participants and 91,000 students who were enrolled in TASC host schools but not participating in TASC projects. [Prepared for the After-School Corporation.]